Keyframe Drawing: Fix 2.7 -> 2.8 regressions

* Outlines of keyframes were too thick and ugly

* Size differences between keyframe types was being swallowed
  by the pixel-fudge factor, leaving colour as the only distinguishing
  factor (bad!)

source/blender/editors/animation/keyframes_draw.c

@@ -492,7 +492,7 @@ void draw_keyframe_shape(float x, float y, float size, bool sel, short key_type,
 			break;
 		
 		default:
-			size -= 0.5f * key_type;
+			size -= 0.8f * key_type;
 	}
 
 	unsigned char fill_col[4];

source/blender/gpu/shaders/gpu_shader_keyframe_diamond_vert.glsl

@@ -2,7 +2,7 @@
 uniform mat4 ModelViewProjectionMatrix;
 
 const float pixel_fudge = sqrt(2.0);
-const float outline_width = 1.25 * pixel_fudge;
+const float outline_width = 1.15 * pixel_fudge;
 
 in vec2 pos;
 in float size;